我曾经能够从命令行启动jupyter Lab。由于我已经更新到Mac OS Catalina，因此我不再能够这样做。我试过将文件移到用户文件夹，以及重新安装anaconda。

Traceback (most recent call last):
  File "/library/Frameworks/Python.framework/Versions/3.7/bin/jupyter",line 10,in <module>
    sys.exit(main())
  File "/library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/jupyter_core/command.py",line 247,in main
    command = _jupyter_abspath(subcommand)
  File "/library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/jupyter_core/command.py",line 134,in _jupyter_abspath
    'Jupyter command `{}` not found.'.format(jupyter_subcommand)
Exception: Jupyter command `jupyter-lab` not found.